26o 



NORTH AMERICAN DIPTHRA. 



First posterior cell with a slum]) of vein from the third longi- 

 tudinal vein: 



Sphyximorpha, 4,11. 

 Microdon, 4, 8, (fig. 1). 



4. Anteniue elongate: 

 Sphyximorpha, 3, 11, (fig. 24 

 Chrysogaster, spp. (fig. 3). 

 Chrysotoxum, 2, 8, (fig. 4). 

 Copestylum, 1, 5, 9, (fig. 14). 

 Lepidostola, 

 Megatnetapon, 5, 10. 

 Microdon, 3, 8. 

 Mixogaster, 3, 9. 



Paragus, spp. 8. 



5. Arista plumose: 

 Arctophila, 2. 

 Brachyopa, spp. 

 Chilosia, spp. 8. 

 Copestylum, 1, 4, S, (fig. 14). 

 Eristalis, spp. 1, 2 (8). 



Mixogaster, 4, 9. 

 Rhopalosyrphus, 4, 8, 9, 10. 



8, 9, 10. 



Pipiza, 8. 

 Platynochaetus, 2. 

 (Phalacromyia), 5. 

 Rhopalosyrphus, 3, 



Rhysops. 

 Sphecomyia, sp. 

 Spilomyia spp. 7, (fig. 23). 

 Volucella, 1, 5, 8. 



Megatnetapon, 4, 8, 10. 

 Condidea, 2. 



Pyritis, 



Serieomvia (fig. 16). 



Volucella, I, 4, 8, (fig 



Epistoma produced into a long, porrect snout 

 Rhingia, Lycastrirhyncha, 1 



Hind femora with a projection below 



I3-) 



2. 



Milesia, 1, 2. 

 Pterallastes, 2, (sp.) 7 

 Senogaster, 2, 9. 

 Eyes pubescent: 

 Chilosia, spp. 

 Chrysotoxum, 4. 

 Ferdinandea. 

 Copestylum, 1, 4, 5. 

 Didea, sp. 2. 

 Eristalis, spp. 1, 2, 5. 

 Leucozona. 

 Mallota, 2, 10, (s])i . 

 Megametapon, 1, 4, 5 



Spilomyia, 4. 

 Tropidia, 2. 



10. 



Microdon, spp. 3, 4, 10. 



Paragus, 4. 



Pipiza, 4. 



Psilota. 



Pyritis, 5. 



Rhopalosyrphus, 3, 4, 9, 10. 



Scseva. 



Syrphus, spp. 



Volucella, 1, 4, 5; or 4, 5. 



9. Abdomen spatulate or conspicuously narrowed at bast-: 



Baccha. 

 Ceriogaster, 2. 

 Mixogaster, 3, 4, S. 10. 

 Neoascia. 



10. Males dichoptic: 

 Asemosyrphus, 2. 

 Chalcomyia. 

 Chamaesyrphus. 

 Helophilus, 2. 



Mallota, s]). 2, 8. 

 Microdon, 3, 4, S. 



1 1. Arista or style of anteniue terminal: 



Rhopalosyrphus, 3 

 Salpingogaster, 2. 

 Sphegina. 

 S])hyximorpha, 3, |, 



4. 8, 10. 



1 1. 



Mixogaster, 3, 4, 9. 

 Megametapon, 1, 4, ,s, 8. 

 Pelecocera, 1 1. 

 Rhopalosyrphus, 3,4. 8, 9. 

 Pterallastes, 2, 7, 1 sp. 1 



Callicera. 

 Pelecocera, 10. 



Merapioidus. 

 Sphyximorpha, 



4.9- 



